Severe Hydroxyapatite Deposition Disease in Binturongs (Arctictis binturong)

In a collection of 6 young binturongs ( Arctictis binturong), 3 presented with anorexia, lethargy, and footpad swelling diagnosed by surgical biopsy as calcinosis circumscripta. Despite supportive care over the next 4 years, affected binturongs had progressive weight loss, hyperphosphatemia, and hyperkalemia and developed large radiodense deposits in tissues adjacent to appendicular joints, thoracolumbar vertebrae, and the sternum. Two binturongs died and necropsies showed severe periarticular mineral deposition with fibrosis and granulomatous inflammation. Additionally, binturongs had mineralization of distal renal tubules, mineralization of the renal interstitium, and marked mineralization of the pulmonary interstitium and peribronchiolar smooth muscle. Foot biopsies from the surviving binturong were evaluated by spectroscopic microanalysis and were positive for hydroxyapatite, Ca10(PO4)6(OH)2. Periarticular and footpad mineralization in these binturongs is consistent with hydroxyapatite deposition disease, which is rarely described in humans and animals as a primary familial condition or a secondary condition often associated with renal injury.

Hydroxyapatite deposition disease of the wrist with intraosseous migration to the lunate bone

Hydroxyapatite deposition disease (HADD) is a mostly uniarticular, self-limiting condition caused by deposition of hydroxyapatite (HA) crystals in tendons or in the peritendinous soft tissues. Commonly, the glenohumeral joint is affected. More rarely, the HA depot can be cause of a carpal tunnel syndrome due to an acute inflammatory reaction and space-occupying soft tissue oedema. We report a case of acute HA depot located at the volar site of the right wrist with affection of the deep flexor tendons and intraosseous migration into the lunate bone in a 50-year-old female. There are two main goals of this case report: First, to remind the diagnosis of HADD as a cause of wrist pain and also of carpal tunnel syndrome, as this entity being often misdiagnosed clinically, and second, to report a rare case of intraosseous migration of HA crystals into the lunate bone.

Mimickers of Hill-Sachs Lesions

The purpose of this article is to describe the imaging appearance, etiology, clinical features, and treatment of rare presentations of common bone and joint diseases known to mimic Hill-Sachs lesions. Knowledge of uncommonly encountered manifestations of ankylosing spondylitis, rheumatoid arthritis, septic joint, hyperparathyroidism, hydroxyapatite deposition disease, malignant bone tumors, and benign bone cysts which mimic traumatic Hill-Sachs lesions is important for radiologists to guide the clinical care of patients who present with shoulder symptoms.

Calcium Hydroxyapatite Deposition Disease

Chapter 37 discusses calcific hydroxyapatite deposition disease (HADD). Hydroxyapatite (HA) crystal deposition disease is a systemic disease of unknown etiology that is caused by periarticular and/or intraarticular deposition of HA crystals. The shoulder is the most commonly involved joint with calcification in the supraspinatus tendon, but not all patients with HADD are symptomatic. Radiography is the main diagnostic tool for HADD, which may show calcifications of varying size and shape in the periarticular tendons, bursae, and joint capsule with joint destruction. Ultrasound can be useful in evaluation and image-guided treatment of calcific tendinitis.